Hey Dennis --
Like Rob we use Google docs, taking "snapshot" downloads every few weeks that we keep locally (in a firebox at my house) just in case.
We keep all of the documents we use to manage properties (lease template, property walkthrough doc, key security deposit form, security deposit form, rent verification, etc.) on the drive all together in one folder so we can simply access that when we need to rent something. All of the other forms like LLC meeting minutes, property price calculators, contact lists, etc. we keep in an organized way in the drive too. Each of our properties has it own folders and sub-folders... So yes, we scan all signed and given paperwork and just keep it in the cloud too, along with the properties individual log, etc.
We looked at Quickbooks but we feel we don't do enough transactions to merit the program. We use Quicken... Measurably cheaper, easier to use, can import what you need, reporting is pretty decent, and our CPA can use it no prob.
Mike